Stimulated Brillouin Scattering in an AlGaN Photonics Platform Operating in the Visible Spectral Range

Abstract

We present Stimulated Brillouin Scattering (SBS) process in AlGaN integrated photonic waveguides. The wide bandgap of this III-Nitride material platform allows operating at visible wavelengths enabling large Stokes shifts. For this study, we employ a multiphysics approach that includes electric-photoelastic, magnetic-photoelastic, material interface displacement effects, and for optimal waveguide dimensions to find the Brillouin-active acoustic modes involved in the SBS process. The SBS power gain and the Stokes frequency shift are investigated for both backward and forward scattering processes, and it is shown that stokes shift larger than 50 GHz with high gain are achievable. Moreover, a parametric analysis is presented in order to demonstrate the possibility of realizing Brillouin lasers operating at blue wavelengths.

Brillouin integrated photonics

“…Germanium waveguides with silica substrate are predicted to exhibit high SBS gains at 4.0 µm 60 . Conversely, in the visible spectrum materials such as AlGaN have been proposed as compact SBS sources 61 . Aluminium nitride is an excellent material for opto-mechanical interactions since it has a very large acoustic lifetime and also because acoustic waves can be directly excited electronically: experiments demonstrating Brillouin scattering from induced acoustic waves have recently been reported .…”